PROJECT SUMMARY Bladder cancer is one of the top 10 cancers in the nation, and the 4th most common cancer in men. The majority (70-80%) of bladder cancer is diagnosed at an early stage, when the cancer is confined to the epithelial and lamina propria layer of the bladder and known as non-muscle invasive bladder cancer (NMIBC). NMIBC can be removed successfully; however, 50-80% of NMIBC recurs within 5 years, with some patients experiencing multiple recurrences at similar stages. Clinical management requires life-long surveillance by cystoscopy for NMIBC patients, amounting to bladder cancer being the most expensive cancer to treat. Novel and cost-effective intervention strategies to control NMIBC recurrence and progression are urgently needed. Our findings from in vitro, in vivo, and epidemiologic studies support that dietary isothiocyanates (ITCs) exert potent anti-cancer activities against bladder cancer. ITCs are a group of phytochemicals primarily derived from cruciferous vegetables and oral consumption of dietary ITCs can be rapidly metabolized, delivered to the bladder and concentrated in the urine, rendering the abnormal bladder epithelium the best target. In our retrospective study, high consumption of raw cruciferous vegetables was associated with reduced bladder cancer-specific mortality and overall mortality. We propose to translate our strong preclinical findings into a novel, dietary behavioral intervention to reduce bladder cancer recurrence and progression in NMIBC patients. We will partner with the New York State Cancer Registry to recruit eligible patients and their clinical care providers in our catchment area, which has a disproportionally high burden of bladder cancer. Specific Aim 1: Develop an evidence-based behavioral intervention to increase cruciferous vegetable intake, with the goal of attaining desirable urinary ITC levels effective for anti-cancer activities. We will work with our Community Advisory Board to adapt materials and methods from current evidence-based fruit and vegetable interventions and leverage our findings on ITC yield from cruciferous vegetables to develop our dietary intervention, using a systematic process consisting of information gathering, discussion groups, and mock intervention delivery. Specific Aim 2: Conduct a feasibility pilot of our dietary behavioral intervention through a hybrid I implementation randomized controlled design in 80 NMIBC survivors, where the treatment group (n=40) will receive an evidence-based telephone intervention to increase cruciferous vegetable intake and the control group (n=40) will receive a general fruit and vegetable intake intervention based on NCI guidelines. Primary outcomes will be cruciferous vegetable intake and urinary ITC levels, and the secondary outcome will be gene expression changes in urinary exfoliated epithelial cells as a surrogate for intermediate efficacy. Exploratory Aim: Engage the clinical care providers of patients enrolled in our intervention to ascertain the barriers and facilitators of intervention implementation within clinical practice through conducting 20 semi-structured interviews. The goal is to gain feedback and refine the intervention for ?real-world' implementation.